Fluid flow fuse



Nov. 4, 1969 A. T|LLMAN 3,476,141

FLUID FLOW FUSE Filed Jan. 13, 1967 481] i INVENTOR ,o BY W r www.ATTORNEYS.

United States Patent C 3,476,141 FLUID FLW FUSE p Y Alfred Tillman,Mount Tabor, NJ., assigner to Marotta Valve Corporation, Boonton, NJ., acorporation of New .Ierse Filgd Jan. 13, 1967, Ser. No. 609,147

Int. Cl. F161( 31/36 U.S. Cl. 137-498 12 Claims ABSTRACT F THEDISCLOSURE to the uid pressure ahead of the restriction and connectedwith the valve element for closing the valve element when the pressuredrop across the restriction exceeds a given value. This pressure drop isa function of the iiow rate. A sleeve on the outside of the housing canbe rotated to change the cross section of the restriction and thusadjust the fuse to operate at different ilow rates.

Brief description of the invention The principal object of thisinvention is to provide an improved iiuid ow fuse for shutting oiffurther flow through a fluid line if the rate of flow becomes excessive,as in the case of a bursted hose or other accident. The inventionprovides an in-line fuse which is not substantially larger in diameterthan conventional fittings for the size of pipe with which the fuse isused.

An important feature of the invention is its adjustability to operate atdifferent flow rates, and the adjustment of the tlow rate from outsidethe housing. A sleeve surrounding the inner part of the housing of thefuse is movable to change the flow rate. In the preferred construction,the sleeve is threaded over an inner portion of the housing so that itmoves axially when rotated, and this axial movement changes therestriction in the ilow passage through the housing so that the pressuredrop is increased or decreased, depending upon the direction ofadjustment, at a given flow rate, and the valve element closes at adifferent ow rate. The actual force for closing the valve element canremain constant and this greata ly simplifies the construction of thefuse.

4Other objects, features and advantages of the invention will appear orbe pointed out as the description proceeds.

Brief description of the drawing Detailed description of the inventionThe fluid ow fuse includes a housing having an inlet fitting 12 at oneend and an outlet fitting 14 at the other end. Both of these ttings arethreaded to receive piping or other fittings of the uid flow line inwhich the Mice fuse `is used. In the preferred construction the fittings12 and 14 are part of the inner portion of the housing l0, andpreferably of one-piece construction with the inner portion of thehousing.

The housing 10 has an outer portion comprising a sleeve 16 which extendsalong most of the axial length of the fuse. This sleeve 16 has threads18 which connect the sleeve with the inner portion of the housing, asshown in FIGURE 4. Rotation of the sleeve 16 causes it to move along itsthreaded connection with the inner portion of the housing and changesthe axial position of the sleeve 16 with respect to the remainder of thefuse.

There is a plastic insert 29, in an opening through the sleeve 16, incontact with the threads on the inner portion of the housing. Thisinsert 20 is pressed against the threads by a screw plug 22, threadedinto the sleeve opening, to maintain a substantial friction between theinsert 20 and the threads on the inner portion of the housing. Acircumferential knurled area 26 provides a convenient grip for rotatingthe sleeve 1-6 with respect to the inner portion of the housing; and thefriction of the insert 20 serves to hold the sleeve in any adjustedposition.

Legends 3l) (FIGURE l) on the outside of the sleeve 16 indicate thedirection in which the sleeve must be rotated in order to increase ordecrease the iiow rate at which the fuse operates to shut olf furtherilow. Axial movement of the sleeve 16 toward the left is limited by asnap ring 34 which tits into a groove 36 in the outlet fitting 14.Limitation of the movement of the sleeve 16 in the other direction willbe explained in connection with the adjustment of the flow passagethrough the fuse housing.

FIGURE 4 shows the flow passage through the housing, and this passageincludes an axial portion 40 of substantial diameter within the inletfitting 12. At the inner end of this axial portion 4t) there are aplurality of angularly spaced radial openings 42 which extendsubstantially normal to the axis of the iiow fuse and which open throughthe wall of the inner portion of the housing into a circumferentialrecess 44. This recess 44 is covered by the outer sleeve 16 and theclearance between the bottom of the recess -44 and the inner surface ofthe sleeve 16 constitutes a part of the iiuid flow passage through thehousing.

At one end of the recess 44 there is a shoulder 46 at which the diameterof the inner portion of the housing increases to substantially theinside diameter of the outer sleeve 16, and at a short distance beyondthis shoulder 46 there is a seal, preferably an O-ring 48, located in agroove in the inner portion of the housing for preventing escape'offluid from the circumferential recess 44 to the outside of the housing.

At the other end of the circumferential recess 44, there is acircumferential ridge 52 formed on the inner portion Vof the housing,and the left-hand side of the ridge 52 provides an annular face 54 whichforms one side of another portion of the flow passage through thehousing. The outer sleeve 16 has a circumferential groove 56 in itsinner surface for providing a clearance for fluid ilow around theperiphery of the ridge 52, and this groove 56 is of sufficient axialextent so that it provides clearance for fluid ow past the periphery ofthe ridge 52 for all adjusted positions of the outer sleeve 16.

The left-hand side of the groove 56 provides an annular face 64 whichconfronts the face 54 along at least a part of the radial extent of thefaces 54 and 64. The clearance between these faces S4 and 64 changesprogressively as the outer sleeve 16 is rotated to .screw it one way orthe other along the inner portion of the housing. For example, as thesleeve 16 moves toward the right in FIGURE 4, the face 64 moves closerto the face 54 and the cross section of the clearance between the faces54 and 64 decreases.

Conversely, movement of the sleeve 16 toward the left increases thecross section of the clearance between the faces S4 and 64. Thisclearance is an adjustable restriction in the flow passage through thefuse housing 1G, and by adjusting the cross section of this restriction,the pressure drop of the uid flowing through the housing of the fuse canbe increased or decreased.

There are other radial openings 66 at angularly spaced locations andextending through the wall of the inner portion of the housing from theregion of the restriction faces 54 and 64 to a chamber 68 which, withthe radial openings 66, form another part of the tluid llow passagethrough the housing.

The fluid ow passage also includes an axial portion 70 in the outletfitting 44; and this axial portion 70 communicates with the chamber 68through a port 72 which has a valve seat 74 at its inner end. A valveelement 76, in axial alignment with the port 72 and the axial portions40 and 70 of the flow passage, is movable toward and from the seat 74 tocommand the passage of fluid through the port 72.

The valve element 76 has a cylindrical portion which slides in a guidebearing 80 formed in the housing, and the valve element 76 is connectedwith a movable wall or piston 82 which reciprocates in a cylindricalchamber 84. The valve element 76 is urged into open position by a spring86 compressed between the piston 82 and a shoulder 88 formed by one endof the cylindrical chamber 84. A snap ring 90 fits into a groove nearone end of the cylindrical chamber 84 and limits movement of the piston82 and the valve element 76 toward the right in FIGURE 4.

The cylindrical chamber 84 communicates with the axial portion 40 of theow passage. Thus the piston 82 is exposed to pressure of the fluid inthe housing upstream of the restriction in the flow passage between theannular faces 54 and 64.

Whenever the pressure drop between the axial portion 40 of the owpassage and the portion of the How passage downstream from therestriction is enough to overcome the force of the spring 86, the valveelement 76 moves into closed position. The actual force required tocompress the spring 86 and to move the valve element 76 into closedposition is always the same since there is no provision for adjustingthe force of the spring 86. However, the actual flow of fluid which willproduce a force suficient to compress the spring 86 depends upon thepressure drop in the ow passage, and more particularly in the portion ofthe llow passage at the restriction between the faces 54 and 64. Thisspring-compressing pressure can be obtained at widely diferent rates oftlow, depending upon changes in the cross section of the clearancebetween the faces 54 and 64. Thus the fuse can be adjusted to close atdifferent flow rates by merely rotating the outer sleeve 16 to screw itone way or another along the inner portion of the housing. The seal 48at one end of the sleeve 16 and a corresponding seal 48 near the otherend of the sleeve, prevent escape of fluid from the housing withoutinterfering with the rotation of the sleeve i6.

What is claimed is:

1. A iluid flow fuse including a housing having a llow passagetherethrough including a valve chamber, said passage having a port atone end of the valve chamber with a valve seat around the peripherythereof, a valve element in the valve chamber movable toward and fromthe port to control the tlow of fluid through the housing, resilientmeans urging the valve element toward its open position, a portion ofthe valve chamber upstream from the seat having a movable wall which isexposed on its upstream side to an inlet pressure in the housing theflow passage having a portion of restricted cross section outside of thevalve chamber and by-passing the movable wall and leading from alocation upstream of the movable wall to a location in the valve chamberbeyond the range of movement of the movable wall and downstream thereof,

and an operative connection between the movable wall and the valveelement, for moving the valve element into closed position, therestriction of the flow passage being correlated with the movable walland said resilient means to move the valve element into closed positionwhen the liow rate through the restriction exceeds a given value.

2. The fluid llow fuse described in claim 1 characterized by a portionof said chamber being cylindrical, and the movable wall closing one endof said cylindrical p0rtion and said operative connection extendingaxially of said cylindrical portion, the valve element, when in openposition, being spaced from the valve seat by a distance that produces afurther restriction of the tiow passage and a second significantpressure drop for causing the valve to `move into closed position whenthe pressure drop exceed said given value.

3. The fluid flow fuse described in claim 2, characterized by thecylindrical portion having a shoulder at one end, and the movable wallbeing a piston in axial alignment with the valve seat, the piston andits operative connection with the valve element both being of integralconstruction with the valve element, the resilient means being a helicalspring located in the cylindrical portion and compressed between thepiston and the shoulder at one end of the cylindrical portion, the valveelement extending into the lluid passage through the seat when the valveelement is in open position, and restricting the fluid flow through thevalve seat port to throttle further the llow of uid from the restrictedby-pass.

4. The luid tlow fuse described in claim 3 characterized by anothershoulder at the other end of the cylindrical portion comprising aremovable stop that locks into the cylindrical portion on the side ofthe piston opposite the spring.

5. A lluid fuse including a housing having a flow passage therethrough,said passage having a port with a valve seat around the peripherythereof, a valve element movable toward and `from the port to controlthe ow of fluid through the housing, resilient means urging the valveelement toward its open position, the housing having a portion of its owpassage, including at least a portion of the flow passage upstream fromthe valve seat, restricted so that a pressure drop occurs thereinproportional to the rate of ow of uid through the housing, a portion ofthe flow passage upstream from the restriction comprising a chamberhaving a movable wall which is exposed to the pressure in the housingbefore said pressure drop, and an operative connection between themovable wall and the valve element, the operative connection and thevalve element being positioned for moving the valve element into closedposition when the pressure drop across the restriction exceeds a givenvalue, and characterized by adjustable means operative from outside ofthe housing for changing the minimum cross section of the restrictedportion of the flow passage upstream from the valve seat to change thepressure drop and thereby change the flow rate at which the valveelement closes against the valve seat to stop the ow through the owpassage.

6. rlhe fluid ow fuse described in claim 5 characterized by theadjustable means including an outer sleeve portion of the housingrotatable on and surrounding at least a part of the length of an innerportion of the housing.

7. The iluid flow fuse described in claim 6 characterized by therestricted portion of the flow passage being a clearance between aninside surface of the sleeve portion and an outside surface of the innerportion of the housing, and the sleeve portion being threaded on theinner portion to obtain axial movement of the sleeve portion on theinner portion in response to rotation of the sleeve portion.

`8. The uid tlow fuse described in claim 6 characterized by therestricted portion of the ow passage extending between confrontingannular shoulders on the sleeve and on the inner portion of the housing,said shoulders being movable toward and from one another to change thecross section of the clearance between them.

9. The fluid llow fuse described in claim 1 characterized by the housingincluding an inner portion and an outer portion movable with respect tothe inner portion, inlet and outlet ports at opposite ends of the innerportion of the housing and in line with one another, making the fuse anin1ine, the restricted portion of the flow passage being adjustable incross section in response to movement of the outer portion of thehousing on the inner portion.

10. The fluid flow fuse described in claim 9 characterized by the innerportion of the valve housing being of circular cross section, radialopenings through the wall of the inner portion at axially spacedlocations on the upsteam side of the valve seat, the outer portion ofthe housing being a sleeve that surrounds the inner portion and that hasa clearance from the outer surface of the inner portion at the radialopenings and along the axial distance between radial openings, saidclearance constituting the restricted portion of the flow passagethrough the housing, and seals at opposite ends of said clearance.

11. The fluid flow 4fuse described in claim 9 characterized by acircumferential ridge on one, and a circumferential groove in the other,of confronting faces of the outer and inner portions of the housing andproviding annular faces that form opposite sides of part of the lengthof the ow passage, the outer portion of the housing being threaded onthe inner portion and movable axially thereon in response to relativerotation of the inner and outer portions with respect to one another tomove the annular surfaces together or apart to change the restriction inthe ow passage and means for controlling the friction of the outerportion on the inner portion of the housing.

12. The fluid ilow fuse described in claim 1 characterized by thehousing having outer and inner concentric portions with confrontingfaces having a clearance between them for a portion of their axiallengths, said clearance constituting a part of the length of the ilowpassage through the housing, a circumferential ridge on one, and acircumferential groove in the other of the confronting faces of theouter and inner portions of the housing and providing annular faces that-form opposite sides of the restricted part of the length of the flowpassage, the outer portion of the housing being threaded on the innerportion and movable axially thereon in response to relative relation ofthe inner and outer portions with respect to one another to move theannular surfaces together or apart to change the restriction in the owpassage, the axial width of the groove Ibeing greater than the axialwidth of the ridge to provide clearance for the ow of iluid along theside of the ridge opposite said annular surfaces.

References Cited UNITED STATES PATENTS 2,710,626 6/1955 Burdick et al.137-498 2,821,209 l/ 1958 Waterman 137-498 2,865,397 12/1958 Chenault13750l XR 3,357,448 12/1967 Martin 137-501 M. CARY NELSON, PrimaryExaminer R. I. MILLER, Assistant Examiner

